Radio spectrum is a limited resource. A large amount of spectrum is required to deliver services that are associated with modern wireless personal communications. Typical examples are smart phone Internet applications, wireless streaming audio, and video, to mention a few. These services consume large amounts of spectral resources causing both financial and spectrum policy issues.
In modern cellular networks spectrum re-use is necessary. A macro cell may cover a large area and additional capacity in local areas is introduced by the use of micro, pico and femtocells. These devices often have lower transmit power than macro cells and they may also share the same spectrum. The interference issue with this type of high spectrum re-use can be severe because a cellular handset may receive macro cell signals and micro cell signals on same frequency and at the same amplitude, depending on location.
This invention describes method to allow a handset to separate desired micro, pico, or femtocell signals from undesired macro base station signals by using orthogonalization of the undesired signals. This method can be built into an existing LTE compliant system with hardware and software modifications without changes to the LTE protocol.